A flooring system of the aforementioned type is disclosed in, for example, DK-C-155,616, in which it is possible to achieve a very effective coupling of the tiles by special projecting coupling parts which can be brought into engagement with complementary coupling means located retracted from the single side edges of the tiles.
While it is no doubt possible to obtain a rigid coupling between the proposed conventional tiles, though in a rather difficult manner conditioned by a pronounced resilient flexibility of the tiles and/or rather high efforts for establishing the locking engagement, it has been found as a considerable drawback that the coupling parts may be broken when the tiles are subjected to external forces and, consequently, the relevant tiles will have to be replaced as they will be without any holding connection with neighboring or adjoining tiles.
This is mainly explainable by the fact that climate conditioned heating and air conditioning of the floor will produce different degrees of associated expansion and contraction of the layers constituted by the rigid support surface and the plastic tile layer thereon, respectively, whereby, for example, a relative contraction of the tile layer will imply large pulling forces in the coupling parts integrally associated with the tiles. The coupling parts may be constructed correspondingly heavily but then without overcoming the associated productional problems relating to a desired minimization of the material consumption of the coupling parts.